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Turlings, Ted
Nom
Turlings, Ted
Affiliation principale
Fonction
Professeur ordinaire
Email
ted.turlings@unine.ch
Identifiants
Résultat de la recherche
Voici les éléments 1 - 2 sur 2
- PublicationAccès libreAn alternative hibernation strategy involving sun-exposed 'hotspots', dispersal by flight, and host plant finding by olfaction in an alpine leaf beetle(2005)
; Oreina cacaliae (Schrank) (Coleoptera: Chrysomelidae) has a 2-year life cycle that it has to complete within the short warm seasons of the harsh alpine environment. Three years of field observations and experiments revealed that not all beetles overwintered in the soil next to their principal host Adenostyles alliariae (Asteraceae), as was previously assumed, but that many O. cacaliae left their host in autumn and flew to overwintering sites that were extensively sun-exposed. In spring, these individuals became active 2 months earlier than their conspecifics that had remained in the soil close to the host plant. These early beetles flew from their hibernation sites against the direction of the prevailing wind. After a random landing in snow, they walked to the spring host Petasites paradoxus (Asteraceae) and fed on its floral stalks, the only plant parts present at that time. A few weeks later, they took flight again to locate newly emerging A. alliariae on which they would feed and deposit larvae as did individuals that had overwintered close to A. alliariae. Leaves of A. alliariae contain pyrrolizidine alkaloids (PAs), which the beetles sequester for their own defence. The dominating PA (seneciphylline) was also found to be present in the floral stalks of P. paradoxus. With additional behavioural assays in the field and laboratory, we demonstrated the importance of plant odours in the short-range host location process. This study reveals a unique hibernation behaviour in which part of the beetle population uses exceptionally warm locations from which they emerge in spring, long before all the snow has melted. This early, but risky emergence allows them to exploit a second, highly suitable host plant, which they locate first by wind-guided flight and then by odour-guided walking. The well-fed beetles then use odour again to move to their principal host plant, on which they reproduce. - PublicationAccès libreAttraction of a Leaf Bettle (Oreina cacaliae) to Damaged Host Plants(2001)
; Early in spring, just after the snow melts, the leaf beetle Oreina cacaliae feeds on flowers of Petasites paradoxus. Later in spring they switch to their principle host plant Adenostyles alliariae. The attractiveness of short- and long-term damaged host plants was studied in a wind tunnel. The spring host P. paradoxus was more attractive to the beetles after it had been damaged overnight by conspecifics or artificially, but not when the plants were damaged half an hour before the wind-tunnel experiments. Contrary to P. paradoxus, the principle host plant, A. alliariae was more attractive shortly after an attack by conspecifics (half an hour before the experiment) compared to a undamaged plant, but lost its increased attractiveness when damaged overnight. The enhanced attraction of damaged plants was longer lasting in the spring host P. paradoxus than in the main host A. alliariae. Volatiles emitted by host plants were collected and gas chromatographic analyses of the odors collected showed qualitative and quantitative differences between damaged and undamaged plants. Among the volatiles recorded, green leaf volatiles and mono- and sesquiterpenes dominated. In overnight damaged P. paradoxus plants with an enhanced attractiveness, limonene was emitted in higher amounts. In freshly damaged A. alliariae leaves, more -humulene and germacrene D were emitted compared to (E,E)--farnesene, whereas in the less attractive A. alliariae plants, more (E,E)--farnesene was emitted compared to -humulene and germacrene D. In the field, the long lasting attraction of flowering P. paradoxus early in the season may facilitate mating in O. cacaliae after a successful overwintering.